Solve for $x$ and $y$ using elimination. ${3x+6y = 66}$ ${-3x-5y = -60}$
Explanation: We can eliminate $x$ by adding the equations together when the $x$ coefficients have opposite signs. Add the equations together. Notice that the terms $3x$ and $-3x$ cancel out. ${y = 6}$ Now that you know ${y = 6}$ , plug it back into $\thinspace {3x+6y = 66}\thinspace$ to find $x$ ${3x + 6}{(6)}{= 66}$ $3x+36 = 66$ $3x+36{-36} = 66{-36}$ $3x = 30$ $\dfrac{3x}{{3}} = \dfrac{30}{{3}}$ ${x = 10}$ You can also plug ${y = 6}$ into $\thinspace {-3x-5y = -60}\thinspace$ and get the same answer for $x$ : ${-3x - 5}{(6)}{= -60}$ ${x = 10}$